Damage to growing plants is commonly controlled by the application of various dusts such as insecticides, pesticides, and fungicides. For treatment of large crop areas, dusting is typically carried out using airplanes or wheel-mounted rigs. For smaller crop areas, dusts are usually applied using hand-held dusting apparatus. However, because dusts used for crop treatment are generally very finely divided and heavily compacted, the use of hand-held apparatus to disperse them can be slow, tiresome work.
U.S. Pat. No. 2,450,205 to Rose discloses a powder dispenser having flexible resilient side members, rigid end members, a powder-exit tube, and an air-circulating tube. The ends of the air-circulating tube are provided with air-pervious, powder-impervious discs to prevent powder from entering it. In one form of the dispenser (cf. FIGS. 3, 4, 5), the powder-exit tube is positioned vertically within the air-circulating tube. In operation, the flexible side members are pressed inward, forcing air into the powder mass and agitating it. Upon release of the side members, the air in the powder mass is drawn inwardly through the powder-exit tube, carrying a portion of the powder with it.
U.S. Pat. No. 2,934,241 to Akesson discloses a dust gun apparatus having a container having a sloping lower end, with an impingement plate at its lowest portion. A small stream of air is directed at the plate, resulting in a small fluidizing zone at the bottom of the container. Fluidized dust is conveyed directly from the fluidizing zone to a venturi providing compressed air that carries the fluidized dust to the gun outlet.
U.S. Pat. No. 3,123,362 to Elvers, Sr. discloses a fertilizer gun having a conical hopper for dry fertilizer. A portion of a water supply from a garden hose is directed through a small bore tube to the bottom of the hopper, where it wets a portion of the dry fertilizer. The resulting slurry is forced up through a central pipe to a venturi, where it joins the main portion of the water supply and transported to a delivery nozzle.
U.S. Pat. No. 3,412, 937 to Chamberlain discloses a spray gun for paint that includes a paint supply container provided with an agitator having a paddle connected to a suspended rod. The agitator is actuated to stir the paint when the trigger of the spray gun is manually operated.
U.S. Pat. No. 4,474,327 to Mattson et al. discloses an apparatus to be used with a hand-held air blower for broadcasting fertilizer or other particulate material over a lawn or garden area. The apparatus, which includes an adapter nozzle with a venturi throat for passage of the discharge air stream and a supply container for the particulate material, provides for a portion of the discharge air stream to agitate and fluidize a localized region of the material in the container and coupling that region with the venturi throat by a suction tube to draw the fluidized material into the adapter nozzle for entrainment with the discharge air stream.
U.S. Pat. No. 4,553,698 to Parker et al. discloses a pneumatic duster apparatus for treating structures that includes a dust reservoir, a source of compressed air that is delivered to the reservoir through a flexible tube to agitate the dust to facilitate emptying the reservoir, and a metal discharge tube that is capable of imparting a friction-induced electrostatic charge to the exiting dust that causes it to adhere to treated surfaces.
U.S. Pat. No. 5,161,473 to Landphair et al. discloses an apparatus for distributing seed that includes a seed supply hopper, an air supply line connected to an air manifold that contains a plurality of outlets and extends to the bottom of the hopper, and a seed tube disposed within the manifold. Seeds are propelled from the bottom of the hopper upwards through the seed tube for metering and distribution.
U.S. Pat. No. 5,779,161 to Dvorak discloses an apparatus to be used with a conventional blower for dispensing powdered and granulated materials. The apparatus includes a container for the particulate material to be dispensed, an outlet tube that extends from the bottom of the container to an outlet orifice at the top of the container that is coupled with the blower, an air inlet tube that is in fluid communication with the end of the outlet tube at the outlet orifice and with a first air inlet orifice for the container, and a second inlet orifice for the container. Preferably, at least one of the air inlet orifices is equipped with a slidable door for controlling the area of the orifice and, consequently, the air flow through the orifice.
There is a continuing need for a hand-held dust apparatus that facilitates fluidizing dense dusts and provides convenient control of their rate of dispersal. This need is well met by the dust apparatus of the present invention.